Borescope inspection port device for gas turbine engine and gas turbine engine using same

ABSTRACT

An adapter to permit borescope access inside a gas turbine engine including a compressor stator having a plurality of compressor stator segments comprises a body portion defining a bore extending longitudinally therethrough from a first end to be disposed adjacent to outside surfaces of adjacent compressor stator segments to a second end to be disposed adjacent to inside surfaces of adjacent compressor stator segments. The bore permits a borescope to enter therethrough. The adapter further comprises an attachment portion for circumferentially coupling at least one compressor stator segment to an outer casing of the gas turbine engine.

This invention was made with Government support under N00019-02-C-3003awarded by the United States Navy. The Government has certain rights inthis invention.

FIELD OF THE INVENTION

This invention relates generally to gas turbine engines, and moreparticularly to borescope inspection port devices for gas turbineengines.

BACKGROUND OF THE INVENTION

Gas turbine engines are commonly equipped with pluggable holes in theirouter casings to allow use of borescopes. These are fiber-optic devicesthat allow visual inspection of the interior of the engine withoutdisassembling it, which is a major advantage to operators. However, thepresence of the hole in the casing tends to locally disrupt the smoothflow of air through the engine along the casing walls. It can also be apath of leakage of high-pressure air into areas where it does notcontribute to the engine's performance. This is true even though theports are filled with a plug that is removed for borescope access, sincethe fit of the plug may not be—and normally is not—perfect.

Because the borescope access hole typically penetrates more than onecomponent of a gas turbine engine, some allowance must be made forvariations in the location of the hole in each of these components. Thisis usually accomplished by making the holes larger than they wouldotherwise need to be for borescope access. The increased size of theholes aggravates the airflow disruption and leakage problem.

One common design for a gas turbine engine compressor uses multiplesegments of stator vanes inserted into the casing. Design features, suchas anti-rotation lugs, fix the stator segments into the casingcircumferentially, preventing them from spinning in place. Although thisapproach provides a number of advantages, it adds a part into the“stack” of engine parts through which the borescope access port mustpenetrate. The port's location is normally fixed by the locations anddesigns of the engine components on the outside of the casings, and ofthe aircraft or other location in which the engine is installed. Thefurther away from the anti-rotation lugs the stator segments' borescopeport is placed, the more variation there can be in the port's locationrelative to the external features, which usually are used to locate theremovable plug itself.

Accordingly, it is an object of the present invention to provide aborescope port and gas turbine engine incorporating such port thatovercomes the above-mentioned drawbacks and disadvantages.

SUMMARY OF THE INVENTION

In a first aspect of the present invention, an adapter, to permitborescope access inside a gas turbine engine having an outer casingincluding a Compressor stator having at least one compressor statorsegment, comprises a body portion defining a bore extendinglongitudinally therethrough from a first end to be disposed adjacent tooutside surfaces of the outer casing to a second end to be disposedadjacent to an inside surface of the at least one compressor statorsegment. The bore permits a borescope to enter therethrough. The adapterfurther comprises an attachment portion for circumferentially couplingthe at least one compressor stator segment to the outer casing.

In a second aspect of the present invention, a gas turbine enginecomprises a compressor section having an outer casing and includes acompressor stator and rotor. The compressor stator includes a pluralityof compressor stator segments. A combustion section communicates withand is disposed downstream of the compressor section relative to adirection of airflow. A gas turbine section communicates with and isdisposed downstream of the combustion section relative to a direction ofairflow. An adapter circumferentially couples at least one of thecompressor stator segments to the outer casing. The adapter includes abody portion defining a bore extending therethrough from at least anoutside surface to an inside surface of an associated compressor statorsegment. The bore permits a borescope to enter therethrough.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevational schematic view of a gas turbine engine withthe engine partially broken away to show a portion of the compressorsection of the engine.

FIG. 2 is a perspective view of an adapter embodying the presentinvention to permit borescope access inside a gas turbine engine.

FIG. 3 is a perspective view of the adapter of FIG. 2 coupled to acompressor section of a gas turbine engine.

FIG. 4 is an elevational view of the adapter of FIG. 2 coupled to acompressor section of a gas turbine engine.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 is a side elevation, simplified view of an example of a gasturbine engine 10. The view is partially broken away to show elements ofthe interior of the engine. The engine 10 includes a compression section12, a combustion section 14 and a turbine section 16. An airflow path 18for working medium gases extends axially through the engine 10. Theengine 10 includes a first, low pressure rotor assembly 22 and a second,high pressure rotor assembly 24. The high pressure rotor assembly 24includes a high pressure compressor 26 connected by a shaft 28 to a highpressure turbine 32. The low pressure rotor assembly 22 includes a fanand low pressure compressor 34 connected by a shaft 36 to a low pressureturbine 38. During operation of the engine 10, working medium gases areflowed along the airflow path 18 through the low pressure compressor 26and the high pressure compressor 34. The gases are mixed with fuel inthe combustion section 14 and burned to add energy to the gases. Thehigh pressure working medium gases are discharged from the combustionsection 14 to the turbine section 16. Energy from the low pressureturbine 38 and the high pressure turbine 32 is transferred through theirrespective shafts 36, 28 to the low pressure compressor 34 and the highpressure compressor 26.

With reference to FIGS. 2-4, an adapter 40 permits access inside a gasturbine engine such as, for example, the gas turbine engine 10 describedby way of example only with respect to FIG. 1. The adapter 40 includes agenerally cylindrical body portion 42 defining a bore 44 extendinglongitudinally therethrough from a first end 46 to a second end 48. Asshown in FIGS. 2 and 3, the bore 44 defined by the body portion 42 isgenerally circular, but can take other shapes. The adapter 40 furtherincludes an attachment portion such as, for example, a flange 50 forcircumferentially coupling compressor stator segments 52a, 52b to anouter casing 51 of the gas turbine engine. More specifically, the flange50 has a first portion 50a extending outwardly from the body portion 42for coupling the compressor stator segment 52a to the outer casing 51,and includes a second portion 50b, extending outwardly from the bodyportion in a direction generally opposite to that of the first portion,for coupling the compressor stator segment 52b to the outer casing 51.The first portion 50a and the second portion 50b of the flange 50 eachdefine a hole 54 extending therethrough for receiving a fastener (notshown) to couple the compressor stator segments 52a, 52b to the outercasing 51.

Preferably, a circumferential portion of an outer wall 56 of the bodyportion 42 is shaped for engaging a similarly shaped portion of at leastone compressor stator segment 52 to prevent rotation of the compressorstator segment and the outer casing 51 relative to each other. As bestshown in FIGS. 2 and 3, for example, the adapter 40 has twocircumferential portions 58a, 58b disposed generally at opposite sidesof the outer wall 56 of the body portion 42 relative to each other. Thecircumferential portions 58a, 58b are each generally flat for engaging asimilarly shaped portion of an associated compressor stator segment toprevent rotation of the compressor stator segment and the outer casingrelative to each other.

Providing the adapter 40, for coupling the compressor stator segments 52to the outer casing 51 in a circumferential direction, with a bore 44for borescope access within a gas turbine engine eliminates variationsin the location of a borescope port relative to the outer casing of thegas turbine engine. The adapter 40 in accordance with the presentinvention allows a smaller and less leak-prone design to be employed,and results in increased engine performance. The gas turbine engine andadapter in accordance with the present invention also reduces the numberof machined components, thus resulting in a lighter and less costlyengine.

As will be recognized by those of ordinary skill in the pertinent art,numerous modifications and substitutions can be made to theabove-described embodiment of the present invention without departingfrom the scope of the invention. Accordingly, the preceding portion ofthis specification is to be taken in an illustrative, as opposed to alimiting sense.

1. An adapter to permit borescope access inside a gas turbine enginehaving an outer casing and including a compressor stator having at leastone compressor stator segment, the adapter comprising: a body portiondefining a bore extending longitudinally therethrough from a first endto be disposed adjacent to outside surfaces of the outer casing to asecond end to be disposed adjacent to an inside surface of the at leastone compressor stator segment, the bore permitting a borescope to entertherethrough, the body portion including an outer wall having a shapedfeature configured to engage a correspondingly shaped feature on the atleast one compressor stator segment; and an attachment portion forcircumferentially coupling the at least one compressor stator segment tothe outer casing, the attachment portion including a flange extendingfrom the outer wall and configured to be secured to the outer casing. 2.An adapter as defined in claim 1, wherein the attachment portionincludes a flange.
 3. An adapter as defined in claim 2, wherein theflange includes a first portion extending outwardly from the bodyportion for coupling one of the at least one compressor stator segmentsto the outer casing, and includes a second portion extending outwardlyfrom the body portion in a direction generally opposite to that of thefirst portion for coupling another of the at least one compressor statorsegments to the outer casing.
 4. An adapter as defined in claim 3,wherein the first and second portions of the flange each define a holeextending therethrough for receiving a fastener to couple an associatedcompressor stator segment to the outer casing.
 5. An adapter as definedin claim 1, wherein the body portion is generally circular in crosssection.
 6. An adapter as defined in claim 5, wherein at least onecircumferential portion of an the outer wall of the body portion isshaped for engaging a similarly shaped portion of the at least onecompressor stator segment to prevent rotation of the compressor statorsegment and the outer casing relative to each other.
 7. An adapter asdefined in claim 5, wherein at least one circumferential portion of anthe outer wall of the body portion is generally flat for engaging asimilarly shaped portion of the at least one compressor stator segmentto prevent rotation of the compressor stator segment and the outercasing relative to each other.
 8. An adapter as defined in claim 5,wherein two circumferential portions disposed generally at oppositesides of an the outer wall of the body portion relative to each otherare each shaped for engaging a similarly shaped portion of an associatedcompressor stator segment to prevent rotation of the associatedcompressor stator segment and the outer casing relative to each other.9. An adapter as defined in claim 5, wherein two circumferentialportions disposed generally at opposite sides of an the outer wall ofthe body portion relative to each other are each generally flat forengaging a similarly shaped portion of an associated compressor statorsegment to prevent rotation of the associated compressor stator segmentand the outer casing relative to each other.
 10. An adapter as definedin claim 1, wherein the bore defined by the body portion of the adapteris generally circular.
 11. A gas turbine engine comprising: a compressorsection having an outer casing and including a compressor stator androtor, the compressor stator including a plurality of compressor statorsegments; a combustion section communicating with and disposeddownstream of the compressor section relative to a direction of airflow;a gas turbine section communicating with and disposed downstream of thecombustion section relative to a direction of airflow; and an adaptercircumferentially coupling at least one of the compressor statorsegments to the outer casing, the adapter including a body portiondefining a bore extending therethrough from at least an outside surfaceto an inside surface of an associated compressor stator segment, thebore permitting a borescope to enter therethrough, the body portionincluding an outer wall having a shaped feature configured to engage acorrespondingly shaped feature on the at least one compressor statorsegment, wherein the adapter further includes a flange for coupling theassociated compressor stator segment to the outer casing.
 12. A gasturbine engine as defined in claim 11, wherein the adapter furtherincludes a flange for coupling the associated compressor stator segmentto the outer casing.
 13. A gas turbine engine as defined in claim 12 11,wherein the flange includes a first portion extending outwardly from thebody portion for coupling one of the at least one compressor statorsegments to the outer casing, and includes a second portion extendingoutwardly from the body portion in a direction generally opposite tothat of the first portion for coupling another of the at least onecompressor stator segments to the outer casing.
 14. A gas turbine engineas defined in claim 13, wherein the first and second portions of theflange each define a hole extending therethrough for receiving afastener to couple an associated compressor stator segment to the outercasing.
 15. A gas turbine engine as defined in claim 11, wherein thebody portion is generally circular in cross section.
 16. A gas turbineengine as defined in claim 15, wherein at least one circumferentialportion of an the outer wall of the body portion is shaped for engaginga similarly shaped portion of the at least one compressor stator segmentto prevent rotation of the compressor stator segment and the outercasing relative to each other.
 17. A gas turbine engine as defined inclaim 15, wherein at least one circumferential portion of an the outerwall of the body portion is generally flat for engaging a similarlyshaped portion of the at least one compressor stator segment to preventrotation of the compressor stator segment and the outer casing relativeto each other.
 18. A gas turbine engine as defined in claim 15, whereintwo circumferential portions disposed generally at opposite sides of anthe outer wall of the body portion relative to each other are eachshaped for engaging a similarly shaped portion of an associatedcompressor stator segment to prevent rotation of the associatedcompressor stator segment and the outer casing relative to each other.19. A gas turbine engine as defined in claim 15, wherein twocircumferential portions disposed generally at opposite sides of an theouter wall of the body portion relative to each other are each generallyflat for engaging a similarly shaped portion of an associated compressorstator segment to prevent rotation of the associated compressor statorsegment and the outer casing relative to each other.
 20. A gas turbineengine as defined in claim 11, wherein the bore defined by the bodyportion of the adapter is generally circular.
 21. A gas turbine engineas defined in claim 11, wherein the adapter is arranged in axialalignment with the compressor section.